Durability of alkali-activated slags has been assessed by measuring the permeability using the beam-bending technique. This nondestructive technique obtains permeability values by measuring the hydrodynamic load relaxation curve of a saturated slender beam of solid paste placed in three-point bending. The impact of activator selection on the permeability of alkali-activated slags has been assessed together with the effects of water-to-precursor ratio, revealing that free silica in the activating solution is the dominant factor controlling permeability.The permeability results have been correlated with nitrogen sorption and mercury intrusion porosimetry to elucidate the percolated pore size controlling permeability. Comparison with existing beam-bending results for ordinary portland cement (OPC) paste shows that alkali-activated slags can be synthesized with permeability having the same order of magnitude as for OPC, indicating that certain alkaliactivated slags are as resistant as OPC to ingress of solutions associated with deterioration processes. K E Y W O R D SAlkali-activated slag, beam bending, durability, mercury intrusion porosimetry, nitrogen sorption, permeability

Visualization of sensor networks, data, and metadata is becoming one of the most pivotal aspects of the structural health monitoring (SHM) process. Without the ability to communicate efficiently and effectively between disparate groups working on a project, an SHM system can be underused, misunderstood, or even abandoned. For this reason, this work seeks to evaluate visualization techniques in the field, identify flaws in current practices, and devise a new method for visualizing and accessing SHM data and metadata in 3D. More precisely, the work presented here reflects a method and digital workflow for integrating SHM sensor networks, data, and metadata into a virtual reality environment by combining spherical imaging and informational modeling. Both intuitive and interactive, this method fosters communication on a project enabling diverse practitioners of SHM to efficiently consult and use the sensor networks, data, and metadata. The method is presented through its implementation on a case study, Streicker Bridge at Princeton University campus. To illustrate the efficiency of the new method, the time and data file size were compared to other potential methods used for visualizing and accessing SHM sensor networks, data, and metadata in 3D. Additionally, feedback from civil engineering students familiar with SHM is used for validation. Recommendations on how different groups working together on an SHM project can create SHM virtual environment and convey data to proper audiences, are also included.

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Heritage structures serve as invaluable records of cultural achievement that should be preserved for future generations. To ensure the successful preservation of these structures, there must be an affordable and effective way to conduct conservation. The objective of this work is to outline an efficient workflow for the structural analysis of preservation projects through a case study on the Morris Island Lighthouse in Charleston, South Carolina. Thorough documentation of the cultural significance and structural condition of the lighthouse was completed through archival research, photogrammetry and crack mapping. Structural Health Monitoring and Distinct Element Modelling were used to analyse past structural damage and the present condition. The behaviour of masonry and crack propagation was evaluated under gravity, wind, wave and seismic loading. The results of these analyses were summarized in a virtual tour and informational modelling environment, which allows the results to be accessed and associated with their physical location on the structure. The benefits and limitations of this process are discussed, and a standardized workflow for efficient structural analysis of cultural heritage is proposed. This article is part of the theme issue ‘Environmental loading of heritage structures’.

The implementation of a culture of seismic risk preparedness is becoming increasingly critical in Europe as the building stock ages and the awareness about seismic risk rises. In this context, the assessment of the seismic vulnerability of existing buildings, followed by the implementation of appropriate retrofitting solutions, can help to substantially reduce the levels of physical damage and economic impact of future events. The central region of Portugal is particularly susceptible to large seismic events and is characterized by the prevalence of historic masonry buildings. This work aims to validate assessment methods for the risk of historical city centers in order to propose management strategies for municipalities and assess the economic impact of large-scale seismic retrofitting. To do this, an application of these methods was performed on the historical city center of Leiria. An in-depth inspection was performed of the entire center and the results were compiled into a database. Using an index-based seismic vulnerability assessment approach, a vulnerability assessment was made for each building. Based on vulnerability and predicted damage, estimates of human and economic losses were made for the city center before and after retrofitting to justify interventions on a broad scale.